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Topic Review (Newest First)

02-15-2013 01:29 PM

WickedFast1

have you had the carb updated! same thing happened to me one time, it drove me crazy, over the winter the carb builder had changed something in the carb metering plates from tubes to jets, it ran great on the dyno but would fall down on the track. he fixed all three carbs.

02-14-2013 03:10 PM

gearheadslife

Quote:

Originally Posted by yorkcounty

Do I even need the 1/2 line? Can I just leave the 1/2 to the pump and then go back to 3/8

yes you can use 3/8's for the return, the fuel moving in the line at all times will help tons, as the psi drops in the line (regulator to carb,) there will be no delay when the regulator opens flow to the carb..
as the column of fuel will be moving, remember as you run through the gears the fuel in the line wants to go backwards, adding to the load to the pump.. with it always moving forward (an item in motion stays in motion) when you need the fuel it'll be there..
make sure you didn't kill the pump with the deadhead regulator and no flow through the pump to cool it..
even after the return line, make sure you have 5-6 psi at carb at the top of every gear..

02-14-2013 01:31 PM

yorkcounty

Do I even need the 1/2 line? Can I just leave the 1/2 to the pump and then go back to 3/8

02-14-2013 08:07 AM

gearheadslife

Quote:

Originally Posted by yorkcounty

Yes it is electric and I have a 10 gauge wire ran to it. I have it ran through a relay off the switch. It's approx. 4 feet from the fuel cell under the truck.

Now the return line issue is very interesting. I am running a deadhead style regulator to the carb. I have 3/8 lines from each side of the regulator to each bowl but no return. I do have a pressure gauge inline and I'm on 7-8 psi.

I wasn't aware that the electric pumps stop after reaching pressure so to speak.

electric pumps DON'T STOP but the dead head regulator shuts off the fuel flow, and then the pump just sit's and spins, the fuel is what cools the pump, and is what lubes it.. what psi you have after you top out 1st gear, the fuel being stopped at the deadhead regulator, and your using it at WOT is your issue, the pump can't get the fuel to move in the 1/ line fast enough.. and the fuel volume in the line works against you..
looss the dead head and add a return line,, problem solved

02-14-2013 06:16 AM

yorkcounty

Yes it is electric and I have a 10 gauge wire ran to it. I have it ran through a relay off the switch. It's approx. 4 feet from the fuel cell under the truck.

Now the return line issue is very interesting. I am running a deadhead style regulator to the carb. I have 3/8 lines from each side of the regulator to each bowl but no return. I do have a pressure gauge inline and I'm on 7-8 psi.

I wasn't aware that the electric pumps stop after reaching pressure so to speak.

02-14-2013 01:05 AM

S10 Racer

Since we are on the subject of fuel pumps and "IF" it is electric, where is the pump mounted? If it's mounted in the engine compartment, that's the incorrect location. Electric pumps have very little suction, they are meant to push the fuel, not pull. It needs to be mounted as close to the fuel cell as possible.

02-14-2013 12:33 AM

gearheadslife

you didn't say. but a few things,
1) is the pump an electric near the fuel cell?
2)if the pump is an engine mounted mechanical. thats problem #1
3) what type regulator, deadhead or return style?

here is why..
1) an engine mounted pump has to pull the fuel and pump it to the carb.. 1/2 fuel line has a lot of fuel to try to suck forward..
if using a deadhead regulator with no return line, the fuel stops when the psi is reached, then when your engine wants more fuel the pump has to get all that fuel to start moving.. at 1/2" in size thats a tall order for a mechanical pump.. and even most electric untill you get to race style pumps.. psi means nothing, volume is where it's at with that big a line..
like said, jet ex. and do you have a fuel pressure gauge hooked up between the regulator and carb?

also if electric pump, is it getting full voltage, a pump that surply that much fuel will draw lottsa amps.. it needs a large power feed or when the amp draw goes up. the voltage will drop.. and the pump won't keep up..

need more info.. but I'd look squarely at the pump and if electric the wiring feeding it..

if a deadhead regulator take it off, and sell it to the next guy with more of a stocker type build.. as you need that volume in the line to be moving at all times, because when you need it, starting to move that much fuel from a standing stop is a tall order for even the best pumps.. and pumps that push that much fuel will burn up with fuel not moving through it..

02-14-2013 12:02 AM

dub

What kind of tranny?

02-13-2013 11:50 PM

skippy89

i would start simple and check vacuum first, then check your timing and total timing. make sure your timing advance is working

02-13-2013 10:38 PM

yorkcounty

Yea tried that too left vent off

02-13-2013 10:32 PM

vinniekq2

Is the fuel cell properly vented?Im grasping at straws,,,,try driving it with the cap off?

02-13-2013 10:28 PM

tresi

Does it stay flat or does it start to take off once you have enough rev's on it?

02-13-2013 09:55 PM

yorkcounty

I am running a fuel cell that came with an 8n outlet. From a dead stop it will bow the tires off and bust the 7000 chip. Go to 2nd and nothing. Yes I can run down the road in second roll into it and its flat.

02-13-2013 09:44 PM

vinniekq2

Re: 1/2 inch line? did you drop the tank and make the pick up bigger too?
Have you tried just slowly accelerating in second and hammering it after 4k to see if it revs to redline?
your engine will use 50 gallons per hour at WOT (depending on HP) that has to be delivered through the small #10 AN fitting or holley fitting,,,w/e you use to fill carb bowls

02-13-2013 09:32 PM

yorkcounty

Haven't tried those yet but I am running 1/2 line.

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